The present exemplary embodiment relates to an apparatus for coating fiber based products. It also finds particular application in conjunction with a coating process including a system for indexing parts to be coated, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like coating and/or manufacturing applications.
A number of disadvantages exist with prior coating machines and part conveyors. For one, prior art part conveyors typically use a spring detent mechanism to maintain the orientation of the part or product to be coated throughout the entire path that the part travels throughout the machine. If for any reason this detent fails or if the part is bumped out of position, the part may be spoiled and/or severe damage could occur to the machine. In addition, other prior art systems use electric components such as sensors, motors, servos, etc. to locate and reorient parts. These systems are not only highly expensive but also prone to reliability issues due to the harsh and unforgiving environment of the coating and heat curing processes.
Still another disadvantage, current chain-on-edge machines use a gear or sprocket attached to the part spindle which engages with a stationary gear/sprocket on the machine to reorient the spindle. The rotational speed of the spindle is thus controlled only by the ratio of the pitch diameters of these driving components and the speed at which the part spindle is moving through the machine. Since only a limited number of combinations of gears/sprockets exist (due to the upper and lower diameter limitations of these driving components), there are only a limited range of speeds at which the part spindle could be rotated. In addition, since a sprocket's diameter will remain constant, it will turn at the same speed in relation to the speed of the chain conveyor, regardless of where it is placed along the chain conveyor path in the machine.
Moreover, the prior art chain-on-edge sprocket systems do not provide for any method to selectively lock or fix the orientation of one or more part spindles in relation to the conveyor chain and/or the direction of travel. Also, such prior art sprocket systems cannot force a rotational stop which could allow inertia to cause the spindle to rotate too far. As such, the part spindles and the parts or products supported thereon, may become randomly oriented which further leads to quality control issues in the manufacturing process.